Wire is typically produced in a rolling mill where, after leaving the furthest downstream roll stand, the wire is coiled into loops that are laid one behind the other on a conveyor. As they move downstream on the conveyor the wire is typically air-cooled (see U.S. Pat. No. 3,231,432) and at the end of this conveyor the loops are dropped onto a centering pin that forms a coil that can be bundled up and taken off for distribution.
More particularly the wire exits from the rolling line and passes first through a water-spray unit that effects an initial tempering/cooling operation. Then the wire is fed to a coiler which forms it into loops which it deposits on a short 1m to 2m long roller-type conveyor that in turn passes the succeeding overlapping loops to a much longer chain-type downstream conveyor. Blowers adjacent the downstream conveyor finish off the cooling. The roller-type upstream conveyor has very closely spaced rollers so that as the wire loops are dropped they cannot get caught; instead they will lie flat. The downstream conveyor is of the open chain type so that air can blow through it onto the loops, but since the loops are already recumbent when delivered by the roller conveyor to it there is no possibility of them catching on it.
Invariably the leading end and trailing end of a piece of wire produced in this manner are not up to tolerance. This is in part due to the fact that the length of wire cannot be fed properly at these leading and trailing ends, that the normally provided water cooling is not effective in the desired manner for the leading end piece, and due to other causes. In any case it is necessary that these off-tolerance pieces be cut off and disposed of; they cannot be left on the finished coil.
The simplest way of doing this is simply to station a worker with a bolt cutter who snips off the first 20m to 30m of wire of each run, and another such piece at the end. Clearly this procedure is inexact and costly. Furthermore the wire is typically advancing at such a rate that this type of manual procedure is fairly difficult.
In another known system such as described in Japanese patent documents 58-195202 and 60-87923 an automatic cutting device is provided at the downstream conveyor for snipping one of the loops somewhat downstream of the leading end of the run and somewhat upstream from the trailing end of the run. Then it picks off a group of the loops upstream or downstream, depending on where the cut is made.
Such a system does not work well in a high-speed rolling operation because the individual turns or loops of wire frequently shift somewhat forward or backward. Thus a loop may shift upstream so that it actually lies upstream of a loop formed of wire that is upstream of it, and similarly a loop can shift downstream so that it is slightly downstream of wire that actually is from a further downstream portion. In this case the cutting/removing machine will snag the entire run and frequently pull a whole portion of the coil being made off the conveyor, making a serious mess and forcing the entire machine to be shut down.